JXB Advance Access originally published online on February 8, 2006
Journal of Experimental Botany 2006 57(6):1253-1262; doi:10.1093/jxb/erj091
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
RESEARCH PAPER |
The effect of transient and continuous drought on yield, photosynthesis and carbon isotope discrimination in sugar beet (Beta vulgaris L.)
1Department of Agroenvironmental Science and Technologies (DiSTA), Viale G. Fanin 44, I-40127 Bologna, Italy
2CNR, Institute of Agroenvironmental Biology and Forestry (IBAF), Via Marconi 2, I-05010 Porano (TR), Italy
* To whom correspondence should be addressed. E-mail: amonti{at}agrsci.unibo.it
Stable carbon isotope discrimination (
13C), photosynthetic performance (A), dry matter accumulation (DW), and sucrose yield (Ys) of sugar beet were evaluated in a glasshouse experiment under transient (TS) and permanent (PS) water stress. A was significantly reduced under drought, to an extent depending on stress duration. The reduced A was strictly associated with a low DW and Ys, the later being 42% lower in PS than control plants (C). Restoring water steeply increased A and the associated leaf traits (RWC, leaf water potential etc.), but the increase of Ys was negligible. Therefore, the negative effects of severe water stress in the early growth period, though reversible on gas-exchange and most leaf traits, can drastically reduce Ys of sugar beet. Furthermore, A seems not to be effective in predicting sucrose accumulation, although it was very effective in detecting the occurrence of plant water stress. The A/Ci model was used to assess the photosynthetic adjustments to continuous or transient drought by calculating the photosynthetic parameters Vcmax and Jmax and then compared with
13C. Mesophyll conductance (gm) was estimated by comparing
13C measured on soluble sugars and gas-exchange data. This approach confirmed the expectation that gm was limiting A and that there was a significant drop in [CO2] from the substomatal cavities and the chloroplast stroma both in favourable and drought conditions. Therefore, the carbon concentration at the carboxylation site was overestimated by 2535% by conventional gas-exchange measurements, and Vcmax was consistently underestimated when gm was not taken into account, especially under severe drought. Root
13C was found to be strictly related to sucrose content (brix%), Ys and root dry weight, and this was especially clear when
13C was measured on bulk dry matter. By contrast, leaf
13C measured in soluble sugars (
s) and bulk dry matter (
dm) were found to correlate weakly to brix% and yield, and this was not surprising as the integration time-scale of leaf
s and
dm were found to be shorter than that of root
13C in bulk dry matter. The effect of water stress on diffusive and biochemical limitations with different integration times ranged from 1 d (leaf
s) to more than 1 month (root
dm).
Key words: A/Ci curve, drought, gas exchange, mesophyll conductance, mesophyll limitation
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
A. Monti, G. Bezzi, and G. Venturi Internal conductance under different light conditions along the plant profile of Ethiopian mustard (Brassica carinata A. Brown.) J. Exp. Bot., May 1, 2009; 60(8): 2341 - 2350. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Galle, I. Florez-Sarasa, M. Tomas, A. Pou, H. Medrano, M. Ribas-Carbo, and J. Flexas The role of mesophyll conductance during water stress and recovery in tobacco (Nicotiana sylvestris): acclimation or limitation? J. Exp. Bot., May 1, 2009; 60(8): 2379 - 2390. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. L. Pons, J. Flexas, S. von Caemmerer, J. R. Evans, B. Genty, M. Ribas-Carbo, and E. Brugnoli Estimating mesophyll conductance to CO2: methodology, potential errors, and recommendations J. Exp. Bot., May 1, 2009; 60(8): 2217 - 2234. [Abstract] [Full Text] [PDF] |
||||
![]() |
U. Niinemets, A. Diaz-Espejo, J. Flexas, J. Galmes, and C. R. Warren Role of mesophyll diffusion conductance in constraining potential photosynthetic productivity in the field J. Exp. Bot., May 1, 2009; 60(8): 2249 - 2270. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Perez-Martin, J. Flexas, M. Ribas-Carbo, J. Bota, M. Tomas, J. M. Infante, and A. Diaz-Espejo Interactive effects of soil water deficit and air vapour pressure deficit on mesophyll conductance to CO2 in Vitis vinifera and Olea europaea J. Exp. Bot., May 1, 2009; 60(8): 2391 - 2405. [Abstract] [Full Text] [PDF] |
||||
